The root object for Graphics::Primitive is the Component. Components contain all the common elements that you'd expect: margins, padding, background color etc.

The next most important is the Container. Containers are Components that can hold other Components. Containers have all the attributes and methods of a Component with the addition of the layout_manager attribute for us with Layout::Manager.

Another important Component is the Canvas. The Canvas differs from other components by being a container for various Geometry::Primitive objects. This allows drawing of arbitrary shapes that do not fit existing components.

After creating all your components, there is a lifecycle that allows them to do their internal housekeeping to prepare for eventual drawing. The lifecycle is: prepare, layout and pack. Detailed explanation of these methods can be found in Component.

Graphics::Primitive::Component has a prepared flag. This flag is set as part of the prepare method (shocking, I know). If this flag is set, then subsequent calls to prepare are ignored. Containers also have a prepare flag, but this flag is not set when calling prepare. A Container's flag should be set by the layout manager. More information may be found with Layout::Manager.